Make Feed provide a disk dictionary.

Frameworks/Data/Feed.swift

@@ -88,6 +88,27 @@ public final class Feed: DisplayNameProvider, UnreadCountProvider, Hashable {
 		get {
 			var d = [String: Any]()
 
+			d[Key.url] = url
+			d[Key.feedID] = feedID
+			if let homePageURL = homePageURL {
+				d[Key.homePageURL] = homePageURL
+			}
+			if let name = name {
+				d[Key.name] = name
+			}
+			if let editedName = editedName {
+				d[Key.editedName] = editedName
+			}
+			if let contentHash = contentHash {
+				d[Key.contentHash] = contentHash
+			}
+			if unreadCount > 0 {
+				d[Key.unreadCount] = unreadCount
+			}
+			if let conditionalGetInfo = conditionalGetInfo {
+				d[Key.conditionalGetInfo] = conditionalGetInfo.dictionary
+			}
+
 			return d
 		}
 	}

Frameworks/RSWeb/RSWeb/HTTPConditionalGetInfo.swift

@@ -36,11 +36,8 @@ public struct HTTPConditionalGetInfo {
 		self.init(lastModified: lastModified, etag: etag)
 	}
 
-	public var dictionary: [String: String]? {
+	public var dictionary: [String: String] {
 		get {
-			if lastModified == nil && etag == nil {
-				return nil
-			}
 			var d = [String: String]()
 			if let lastModified = lastModified {
 				d[HTTPResponseHeader.lastModified] = lastModified